The United States announced in March the signing of a new nonproliferation assistance agreement and reported the successful completion of another. The National Nuclear Security Administration announced March 19 that it had completed converting a research reactor in Uzbekistan from running on highly enriched uranium (HEU) to low-enriched uranium (LEU), which cannot be readily used in nuclear weapons. The conversion was done as part of a 2005 agreement between Russia and the United States to work jointly toward converting U.S.- ...